"relative time" for "entire week before last week"


According to the documentation here, last week codes to 1w/w and the 2 last weeks codes to 2w/w. But how to code for the entire week before last week or even the one before again?

I’ve got a dashboard with a variable that is used in the relative time field of the query. My idea is to select the week I’m interested in by just selecting the week from this variable drop-down. It works, of course, when I use the dashboard’s time picker with absolute time…


I found the answer by myself (following example for month, not week):
Relative time: now/M
Time shift:
0M/M for the current month
1M/M for the previous month
2M/M for the 2nd to last month
and so on.